Tata Motors — complaints for delaying in service

Address:

Kolkata, West Bengal, 700014

To
The manager
Tata motors
India.
I have a new tata zest (Nmbr: wb19h 6229) purchased on decemberkshire and it is on road from january
I am facing a some start up problem in my vehicle and had submit it for servicing at tata kb motors at tiljala kolkata on thursday 17th august2017.
But the problem is still unsolved till today they are keep on saying that they can't get the problem. And informed me that a mechanical engineer from has also check it and he is also failed to get the problem. What kind of vehicle it is? Is it for our comfortable or for making a trouble only.
Is it my fault to believe a well known company like tata motors. I am felling my self #.
As it is a commercial vehicle and my instalment ready and it's at service station for 6 days and still there is no hope to get it in comingeneral week.
It's really unprofessional and trouble some. What should i do now. Solve the problem and extend my instalment date which is due on 2nd september2017.
It's not possible for me to pay it in this situation. As the vehicle is at service centre and i must sitting idle at home and it's very difficult for me to meet the ends meet.
What i need to do now whether the problem will solve soon or i need to visit consumer court.
Please reply positively as soon as possible.
Thanking you.
Yours faithful